diff --git a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
index d9ae0ac94818..42829cdaf06d 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
@@ -2021,6 +2021,16 @@ Superuser created successfully.
           file.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          hydrus has been upgraded from version <literal>438</literal>
+          to <literal>462</literal>. Since upgrading between releases
+          this old is advised against, be sure to have a backup of your
+          data before upgrading. For details, see
+          <link xlink:href="https://hydrusnetwork.github.io/hydrus/help/getting_started_installing.html#big_updates">the
+          hydrus manual</link>.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
 </section>
diff --git a/nixos/doc/manual/release-notes/rl-2111.section.md b/nixos/doc/manual/release-notes/rl-2111.section.md
index ceac3c60e8d9..875cd6fae879 100644
--- a/nixos/doc/manual/release-notes/rl-2111.section.md
+++ b/nixos/doc/manual/release-notes/rl-2111.section.md
@@ -547,3 +547,5 @@ In addition to numerous new and upgraded packages, this release has the followin
 - `julia` now refers to `julia-stable` instead of `julia-lts`. In practice this means it has been upgraded from `1.0.4` to `1.5.4`.
 
 - RetroArch has been upgraded from version `1.8.5` to `1.9.13.2`. Since the previous release was quite old, if you're having issues after the upgrade, please delete your `$XDG_CONFIG_HOME/retroarch/retroarch.cfg` file.
+
+- hydrus has been upgraded from version `438` to `462`. Since upgrading between releases this old is advised against, be sure to have a backup of your data before upgrading. For details, see [the hydrus manual](https://hydrusnetwork.github.io/hydrus/help/getting_started_installing.html#big_updates).